Conventional boat hoists in the main include a number of submerged vertical posts comprising a framework which rests upon the floor of the water about the hoist, and with a platform mounted in relation to all of the posts for supporting a boat thereon and movable upwardly and downwardly on the posts by means of a winch and cable assembly.
With the advent of smaller boats generally termed personal watercraft, one trade name being a JET SKI, it has been found that less complicated and smaller hoists may be utilized in connection with an adjacent pier or dock for stability of support. This type boat hoist may be readily installed and removed for ease of use.
The prior art in this field shows, for example, a single dock mounted post the lower end of which is supported on the water floor and a wheel assembly for rolling an H-platform up and down in U.S. Pat. No. 4,678,366. A later U.S. Pat. No. 4,983,067 discloses a vertical post for placement on the water floor and also to an adjacent dock, a lift cradle similar to a fork lift arrangement movably mounted on the post by a winch and cable arrangement.
A most recent patent, U.S. Pat. No. 5,245,940 again shows a vertical post driven into the bottom of the body of water, a platform rollably mounted for vertical movement on the post as by a cable arrangement, but again with a rather large and cumbersome H-type platform. It is evident, therefore that various areas of improvement exist in this relatively new field of boat lifts or hoists.